Application of Relativistic Quantum Chemistry to the Electronic Energy Levels of the Uranyl Ion

Zhang, Zhiyong; Pitzer, Russell M.

doi:10.1021/jp991867q

Cited by 96 publications

(136 citation statements)

References 67 publications

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“…30͒ or SOC-CI. 28,29 On the other hand, for ͓UO 2 Cl 4 ͔ 2− Table VII also includes the experimental data obtained from the detailed experimental analysis of Denning and co-workers of the solid state spectrum of Cs 2 UO 4 Cl 4 . 24,25 Looking first at the U-O distances and frequencies we note the following trends.…”

Section: B Results With Spin-orbit Couplingmentioning

confidence: 99%

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Electronic spectrum of UO22+ and [UO2Cl4]2− calculated with time-dependent density functional theory

Pierloot

Besien

Lenthe

et al. 2007

The Journal of Chemical Physics

104

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The electronic spectra of UO 2 2+ and ͓UO 2 Cl 4 ͔ 2− are calculated with a recently proposed relativistic time-dependent density functional theory method based on the two-component zeroth-order regular approximation for the inclusion of spin-orbit coupling and a noncollinear exchange-correlation functional. All excitations out of the bonding u + orbital into the nonbonding ␦ u or u orbitals for UO 2 2+ and the corresponding excitations for ͓UO 2 Cl 4 ͔ 2− are considered. Scalar relativistic vertical excitation energies are compared to values from previous calculations with the CASPT2 method. Two-component adiabatic excitation energies, U-O equilibrium distances, and symmetric stretching frequencies are compared to CASPT2 and combined configuration-interaction and spin-orbit coupling results, as well as to experimental data. The composition of the excited states in terms of the spin-orbit free states is analyzed. The results point to a significant effect of the chlorine ligands on the electronic spectrum, thereby confirming the CASPT2 results: The excitation energies are shifted and a different luminescent state is found.

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Section: B Results With Spin-orbit Couplingmentioning

confidence: 99%

“…26,27 The experimental data indicate that the energy of the low-lying excited states is relatively independent of the nature of the equatorial ligands. The first detailed ab initio calculations 28,29 were performed using a combined configuration-interaction ͑CI͒ and spin-orbit coupling method, denoted as SOC-CI. …”

Section: Introductionmentioning

confidence: 99%

Electronic spectrum of UO22+ and [UO2Cl4]2− calculated with time-dependent density functional theory

Pierloot

Besien

Lenthe

et al. 2007

The Journal of Chemical Physics

104

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“…For the most common uranium compounds, which have U(VI) and U(IV) oxidation states, the actual U orbital population is approximately two 5f electrons and one or two 6d electrons [23,24]. Since outer orbitals are more profoundly affected by inner orbitals than vice versa, we decided to optimize the s, p, d, and f basis functions for the 5f 2 6d…”

Section: Actinide Basis Setsmentioning

confidence: 99%

“…The pVDZ basis sets for O and U 2+ are given in Ref. [24]. All basis sets will be contributed to the repository described in Ref.…”

Section: Actinide Basis Setsmentioning

confidence: 99%

Atomic orbital basis sets for use with effective core potentials

Blaudeau

Brozell

Matsika

et al. 2000

Int. J. Quant. Chem.

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ABSTRACT:Basis sets developed for use with effective core potentials describe pseudo-orbitals rather than orbitals. The primitive Gaussian functions and the contraction coefficients in the basis set must therefore both describe the valence region effectively and allow the pseudo-orbital to be small in the core region. The latter is particularly difficult using 1s primitive functions, which have their maxima at the nucleus. Several methods of choosing contraction coefficients are tried, and it is found that natural orbitals give the best results. The number and optimization of primitive functions are done following Dunning's correlation-consistent procedure. Optimization of orbital exponents for larger atoms frequently results in coalescence of adjacent exponents; use of orbitals with higher principal quantum number is one alternative. Actinide atoms or ions provide the most difficult cases in that basis sets must be optimized for valence shells of different radial size simultaneously considering correlation energy and spin-orbit energy.

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“…Examples are open-shell systems of heavy p, d, and f elements [1][2][3] and excited states of molecules with closed-shell ground states, for example, in uranyl 4 and coinage metal dimers. 5 Ideally, all of these contributions should be treated on the same footing and, where appropriate, simultaneously.…”

Section: Introductionmentioning

confidence: 99%

The generalized active space concept for the relativistic treatment of electron correlation. III. Large-scale configuration interaction and multiconfiguration self-consistent-field four-component methods with application to UO2

Fleig

Jensen

Olsen

et al. 2006

The Journal of Chemical Physics

126

109

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We present an implementation for large-scale relativistic electronic structure calculations including spin-dependent contributions and electron correlation in a fully variational procedure. The modular implementation of the double group configuration interaction ͑CI͒ program into a multiconfiguration self-consistent-field ͑MCSCF͒ code allows for the treatment of large CI expansions in both the spinor optimization step and the post-MCSCF dynamic electron correlation step. As an illustration of the potential of the new code, we calculate the spectroscopic properties of the UO 2 molecule where we study the ground state and a few excited states in vertical and adiabatic calculations.

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Application of Relativistic Quantum Chemistry to the Electronic Energy Levels of the Uranyl Ion

Cited by 96 publications

References 67 publications

Electronic spectrum of UO22+ and [UO2Cl4]2− calculated with time-dependent density functional theory

Electronic spectrum of UO22+ and [UO2Cl4]2− calculated with time-dependent density functional theory

Atomic orbital basis sets for use with effective core potentials

The generalized active space concept for the relativistic treatment of electron correlation. III. Large-scale configuration interaction and multiconfiguration self-consistent-field four-component methods with application to UO2

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